Fluid operated throttle actuator



May 24, 1966 H. v. KRAuTwuRsT ETAL 3352385 FLUID OPERATED THROTTLE ACTUATOR Filed Sept.

mw W M5 [My United States Patent O 3,252,285 FLUID OPERATED THROTTLE ACTUATOR Homer V. Krautwurst and Edward H. Seidewand, Rochester, N.Y., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Sept. 5, 1963, Ser. No. 306,830 4 Claims. (Cl. 60-54.5)

This invention relates to means for retarding the closure of a hydraulically actuated internal com'bustion engine throttle valve.

Since an engine connected to an automatic transmission has a tendency to stall upon a sudden closure of the throttle valve, it has 'become common to provide most carburetors with a device which will slow the final closing movement of the throttle valve and reduce the stalling tendency. The present invention provides a novel means to slow the throttle valve closure.

The present invention constitutes an i-mprovement over a prior hydraulic actuator 'for an internal combustion engine throttle valve wherein the engine operator controls a master cylinder at one end of a hydraulic circuit. The master cylinder creates pressure variations which are transmitted through the circuit to a servo. The servo opens the throttle valve in response to pressure increases.

Included in the servo of this prior actuator is a valve which retards pressure transmittal by fluid displacement in a throttle valve closing direction after predetermined throttle valve closure. By retarding the fluid flow, the rate of closing of the throttle valve, and thus the stalling tendency, is reduced.

H'In the present invention, the plunger which acts as a connecting link |between the diaphragm in the servo and the throttle lever is constructed to abut against the diaphragm instead of being secured to the diaphragm as has |been formerly done. The plunger, instead of the diaphragm, is biased in the throttle valve closing direction. This construction permits the throttle valve to be actuated by a mechanic at the carburetor end of the linkage, as is often the case, without creating -a vacuum against the diaphragm. By preventing the creation of a vacuum, the present invention prevents -buckling of the diaphragm and promotes longer life thereof.

In the present invention the retarding valve is supported independently of the diaphragm, and improper alignment of the valve by the diaphragm is thus avoided.

By providing an independent plunger and valve support, the present invention also allows the diaphragm to be formed 'without an apert-ure, thus reducin-g the 'possibility of hydraulic fluid leakage.

The present invention additionally incorporates a retarding valve in which the restricted fiow is around the exterior of the valve instead -of through the valve as previously done. The small, easily clogged restriction through the valve is thus obviated. Wear on the valve from the valve seat is also obviated, thus permitting a valve construction from plastic rather than more expensive materials.

The details as well as other objects and advantages of the present invention appear in the accompanying specification and the drawing, in which:

FIGURE l is a schematic view of the throttle actuating means and its connections to the carburetor and to the accelerator foot pedal; and

FIGURE 2 is a sectional view of the housing containing the pressure Sensitive member to which the throttle valve is connected, enlarged to show in detail the pressure flow retarding valve.

Referring first to FIGURE 1, the accelerator pedal or lever is shown mounted on the floor board 12 of the vehicle operatoris compartment. A master cylinder housing 14 contains the first presure Sensitive member 15 to which accelerator pedal 10 is connected by a rod 16. A second housing or servo '18, in which is contained the second pressure Sensitive member, is connected to housing 14 by a flexible hose or conduit 20. Housing 1-8 is secured to the carburetor 22 by a bracket 24.

As shown in FIGURE v2, the second pressure sensitive member or diaphragm 26 is retained in housing '18. A cup-shaped member 28 is secured to diaphragm 26. Abutting member 2'8 is a plunger 30 which controls the throttle valve 32 (FIGURE 1) through a throttle lever '34 and an adjustable link 36. Plunger 30 is biased toward the position shown by a throttle return spring 38. 'Spring 38 acts through plunger 30 on diaphragm 26 against the force of hydraulic fluid within a chamber 40 formed 'by housing 18 and diaphragm 26.

By providing plunger 30 with an abutting connection to diaphragm 26, link '36 and plunger 30 may be manually moved toward the left to open the throttle valve without affecting diaphragm 26. Were diaphragm 26 to be secured to plunger 30 it would also move, creating a vacufum in chamber 40 and causing buckling of diaphragm 26. By avoiding this, the present invention promotes a longer diaphragm life. I

A restricting valve 42 is supported by a member 44 within chamber 40. Member 44 is biased toward the left as viewed in the drawing by a spring 46. Valve 42 is biased by a spring 4'8 interposed .between member 44 toward a reduced portion 50 of conduit 20.

As accelerator pedal '10 is depressed, the pressure of hydraulic fluid against the first pressure Sensitive member '15 is increased, causing the hydraulic fluid to flow out of housing 14 and through conduit 20 to chamber 40. Valve 42 is pressed 'back against spring 48 and offers no obstruction to the flow of fluid into chamber 40. Openings 52 in an internal extension 54 of conduit 20 andopenings 56 in member 44 permit free circulation of hydraulic fluid within chamber 40. (Extension 54 also serves as a guide for member 44.) The flow of lfluid into chamber 40 increases the pressure against the diaphragm 26 and causes movement of diaphragm 26 toward the left against plunger 30 and the biasing action of spring 38, thereby opening throttle valve 32. When accelerator pedal 10 is' released, the pressure of the first pressure Sensitive member on the hydraulic fluid is reduced. Hydraulic fluid then fiows into housin'g 14 from conduit 20 and chamber 40 .because vof the biasing action ofspring 38 on diaphragm 26. The flow of fluid from chamber '40 reduces the pressure against the right side of diaphragm 26, and diaphragm 26 and plunger 30 are moved toward the right by spring 38, beginning to close throttle valve 32.

As diaphragm 26 moves toward the right, it abuts against member 44, moving mem-ber 44 against spring 46. As vmember 44 moves toward the right, valve 42 enters reduced portion 50 of conduit 20 and restricts the flow of hydraulic fluid therethrough -to the annular clearance forme-d by the head of valve 42 and portion 50. The movement of member 26 and the return of closure 32 is thereby slowed.

Recalling that prior to the time valve 42 restricts portion 50 of conduit 20 no restriction is presented to the (flow of fluid from chamber 40, that valve 42 is pressed back against spring 48 by displacement of the fluid from conduit 20 to chamber 40-d'uring initial throttle valve opening and offers no obstruction to the flow of fluid into chamber 40, and that diaphragm 26, member 44, and valve 42 are all dis-placed to the left during greater throttle valve opening, it will -be appreciated that valve 42 offers a restriction to the displacement of hydraulic fluid only during the |final closing movement of throttle valve 32. This reduces the rate at which throttle valve 32 closes and reduces the tendency of the engine to stall.

It should also be emphasized that the closing rate or final retardation of throttle 32 can be calibrated or modulated to obtain the desired closing characteristic by varying the taper or formation of the inner surface of portion 50 or end of valve 42 or both.

We claim:

1. An actuator for an internal combustion engine throttle valve comprising conduit means adapted to contain a fluid through which pressure variations may be transmitted, movable means enclosing one end of said conduit means -and adapted to lbe manually operated to cause pressure variations in the fluid contained therein, second movable means enclosing the other end of said conduit means and adapted to be connected to the throttle valve to cause movement of the throttle valve in response to fluid pressure variations in said conduit means, and valve means supported insaid conduit means and locatable by the displacement of the fluid therethrough to allow relatively unrestricted fluid displacement in a throttle valve opening direction and relatively unrestricted fluid displacement in a throttle valve closing direction during predetermined movement of said second movable means in a throttle valve closing direction and relatively restricted fluid displacement after predetermined movement of said second movable means in a throttle valve closing direction to thereby lower the rate of throttle valve closing after predetermined closure thereof, said conduit means having reduced and enlarged portions, said valve means comprising a member adapted to be located in said enlarged portion of said conduit means to allow relatively unrestricted fluid displacement around said member and to be located in said reduced portion of said conduit means to cause relatively restricted fluiddisplacement around said member.

2. The actuator of claim 1 which further includes means biasing said member to locate said member in said reduced portion of said conduit means to restrict fluid displacement in a throttle valve closing direction.

3. The actuator of claim 2 which further includes other means adapted to support said valve means and locate said member of said valve means and means biasing said other means to locate said member in said enlarged portion of said conduit means, said other means abutting said second movable means and being movable by movement of' said second movable means in a throttle valve closing direction after predetermined movement of said second movable means in a throttle valve closing direction to locate saidmember in said reduced portion of said conduit means to restrict fluid displacement in a throttle valve closing direction..

4. Means for controlling opening and closing movement of an internal combustion engine throttle valve comprising a member adapted to be connected to the throttle valve to control movement thereof, means biasing said member in a throttle valve closing direction, a servo having a flexible diaphragm abutting against said member and responsive to pressure increases to move said member in a throttle valve opening direction, a master cylinder having movable means adapted to be manually operated to cause pressure variations, a fluidcontaining conduit connecting said master cylinder and said servo for transmitting pressure variations from said movable means to said diaphragm, valve means associated With said servo operable by the displacement of the fluid to allow relatively unrestricted fluid displacement in a throttle valve opening direction and relatively unrestricted fiuid displacement in a throttle valve closing direction during predetermined movement of said diaphragm in a throttle valve closing direction and relatively restricted fluid displacement after predetermined movement of said diaphragm in a throttle valve closing direction to thereby lower -the rate of throttle valve closing after predetermined closure thereof, said conduit having a reduced portion, said valve means comprisingan associated valve member adapted to :be located out of said reduced portion-of said conduit to allow 'relatively unrestricted fluid displacement and to be located in said reduced portion of said conduit to cause relatively restrictedv fluid displacement in a throttle valve closing direction, and means biasing said valve member to locate said valve member in said reduced portion of said conduit, supporting means adapted to support and locate said valve member, and means biasing said supporting means to locate' said valve member out of said reduced portion of said conduit, said supporting means being movable by movement of said diaphragm in the throttle valve closing direction after predetermined movement of said diaphragm in a throttle valve closing direction so as to locate said valve member in said reduced portion of said conduit. i

References Citedl by the Examiner UNITED STATES PATENTS 2,185,277 1/1940 lStelzer -545 SAMUEL LEVINE, Primary Examner.

ROBERT R. BUNEVICH, Examner. 

1. AN ACTUATOR FOR AN INTERNAL COMBUSTION ENGINE THROTTLE VALVE COMPRISING CONDUIT MEANS ADAPTED TO CONTAIN A FLUID THROUGH WHICH PRESSURE VARAITIONS MAY BE TRANSMITTED, MOVABLE MEANS ENCLOSING ONE END OF SAID CONDUIT MEANS AND ADAPTED TO BE MANUALLY OPERATED TO CAUSE PRESSURE VARIATIONS IN THE FLUID CONTAINED THEREIN, SECOND MOVABLE MEANS ENCLOSING THE OTHER END OF SAID CONDUIT MEANS AND ADAPTED TO BE CONNECTED TO THE THROTTLE VALVE TO CAUSE MOVEMENT OF THE THROTTLE VALVE IN RESPONSE TO FLUID PRESSURE VARIATIONS IN SAID CONCUIT MEANS, AND VALVE MEANS SUPPORTED IN SAID CONDUIT MEANS AND LOCATABLE BY THE DISPLACEMENT OF THE FLUID THERETHROUGH TO ALLOW RELATIVELY UNRESTRICTED FLUID DISPLACEMENT IN A THROTTLE VALVE OPENING DIRECTION AND RELATIVELY UNRESTRICTED FLUID DISPLACEMENT IN A THROTTLE VALVE CLOSING DIRECTION DURING PREDETERMINED MOVEMENT OF SAID SECOND MOVABLE MEANS IN A THROTTLE VALVE CLOSING DIRECTION AND RELATIVELY RESTRICTED FLUID DISPLACEMENT AFTER PREDETERMINED MOVEMENT OF SAID SECOND MOVABLE MEANS IN A THROTTLE VALVE CLOSING DIRECTION TO THEREBY LOWER THE RATE OF THROTTLE VALVE CLOSING AFTER PREDETERMINED CLOSURE THEREOF, SAID CONDUIT MEANS HAVING REDUCED AND ENLARGED PORTIONS, SAID VALVE MEANS COMPRISING A MEMBER ADAPTED TO BE LOCATED IN SAID ENLARGED PORTION OF SAID CONDUIT MEANS TO ALLOW RELATIVELY UNRESTRICTED FLUID DISPLACEMENT AROUND SAID MEMBER AND TO BE LOCATED IN SAID REDUCED PORTION OF SAID CONDUIT MEANS TO CAUSE RELATIVELY RESTRICTED FLUID DISPLACEMENT AROUND SAID MEMBER. 